1. Field of the Invention
The present invention relates generally to plastic containers for holding, organizing and securing optical disks.
2. Description of the Related Art
Stackable containers have long been used in the prior art. Typically, containers with stackable properties use threaded male/female sections. The top female section is constructed with internal threads. This section screws into the male bottom section. The male bottom section is constructed with an additional attached molded female section which is also a container. Several such containers can be combined to form a stack of containers. These types of threaded containers are generally more expensive and much slower to manufacture than “snap-together” containers. Because threaded containers also allow dirt and debris in the threads, threaded containers often have difficulty closing properly. Further, threaded containers are frequently much taller in height due to the minimum amount of threads needed to make the container screw together. Indeed, most threaded containers are at least about 0.375 inches high. Threaded containers also require stiffer plastic and thicker side walls because of the threaded side wall pressures. Soft plastics like polypropylene are typically not suitable for threaded containers because the threads may strip if over-tightened.
Other containers that use stacking properties are found in the houseware industry. A houseware stackable containers have covers with ribs that match the bottoms of matching containers. The raised rib around the perimeter of a container's lid is larger than the bottom of the container to be stacked on the cover. The bottom nests into the lid. This container relies on gravity and internal weight to stay together. If the containers are dropped, the stack of containers simply falls apart.
Other containers in the prior art use a “friction fit” lid and bottom. This type of container has a lid which has a raised center section approximately 0.050 inches per side smaller than the outside diameter of the container. This area is raised 0.030 inches to 0.050 inches from the rest of the lid. The bottom of the container which forms the container has a ring a few thousands smaller than the top raised center section. The bottom will fit so that the friction that is created will hold the next container set next to the previous container set. Typically, a container set is made of one top and one bottom. A stack is made up of two or more container sets stacked on each other. This method of stacking containers is expensive because of the extra parts required to manufacture the container.